Improved apparatus for the manufacture of paper-pulp



JOHN W. DIXON AND GEORGE HABDING, OF PHILADELPHIA, PA.

IMPROVED APPARATUS FORATHE MANUFACTURE OF PAPER-PULP.

Specification forming part of Letters Patent N0. al, dated May 8, 1866.

reference being had to the annexed drawing,

making a part of this specification, in whichrepresents a strongdigester, capableof resistmg heavy pressure. B is alower perforateddiaphragm, having a passage, O, for the escape of the pulp. Below B is aspace, E n', for they accumulation of the liquid. The passage O isclosed by a valve at D or at F, except when the pulp is to escape.

In this particular apparatus the digester is shown as heated by fireplaced below the digester, although all of the improvements hereindescribed, except one combination, could be used with any otherform ofheating apparatus. A circulating tube passes from below the diaphragm Bto the upper part of the digester. In the course of this tube a rotaryor reciproeatin g pump, I-I, is placed. This pump is to be driven bymachinery, andproduces a constant circulation of the digestingliquidfrom the lower chamber, E, below the diaphragm, through G, into theupper part of the digester, or, vice versa, from the upper part of thechamber down through tube G and the pump into the bottom of thedigester, and thence upl land opening cock 3 the pump can be made towardly, by virtue of the force of the pump, through the mass to bepulped. When it is desired to withdraw the pulp the valves Dand F may beboth opened and the material permitted to escape directly on the valve.D may be first opened, and the material permitted to pass into thetubular space or passage between D and F, and then, when the valve D isclosed and the valve F opened, the material between D and F will escape.

In order to facilitate the withdrawal of the valve D and prevent thepulp from escaping with too great a shock a small steam-pipe extendsfrom the upper part of the digester into the space between D and F, andby opening the cock 1 the pressure on both sides of D is put inequilibrium. This cock is to be closed before F is opened. In this way aportion of the contents can be quietly withdrawn at any time whilethepulpingoperationis still goin gon,

Theoperation of the apparatus is as follows: The wood, straw, or othermaterial, in a nely divided state, is to be introduced through theman-hole at the .top of the digester A. A solution of caustic soda, orlime, or water alone, or other digestingliquid, is to be introduced, andwhen the digester is closed up heat is to be applied below to the bottomof the digester, and the pump started, the cocks 2 being open `and cocksl Iand 3 closed. The pump may be operated so as to force the liquid frombelow B through G into the top of the digester, whence it would descendthrough the material being pulped, or the pumps may be used to force theheated liquor vice versathat is, up through the diaphragm B and throughthe mass being pulped to the top of the digester, whence it woulddescend outside through G again into the pump and the bottom of the digester. p

Fresh material may be introduced while the operation is going on byopening the valve K and introducing the charge of wood, &c., between thevalve K and valve L. `The valve K is then to be closed and the valve Lopened, when the charge falls by its own gravity into the boiler.

In order to relieve the valves of pressure from the inside we employ thetube p, when the cock 4 places the space between K and L in equilibriumwith the digester by causing steam to pass between K and L.

By opening the cock l and closing cock 2 force fresh water or liquidinto the bottom ofthe digester from a heating apparatus, T, or tank T,(such as described in a former patent of J. W. Dixon,) where it becomesheated, and then up through the material, and the refuse liquid couldpass through cock 3 into the coil U U U U, and thus heats the incomingliquid entering through cock 1 in the manner fully described in otherpatents heretofore granted to us. The introduction of fresh water belowVinto the digester, in combination with the introduction of fresh chargesof material above, would cause the fresher water always to bein 4contactwith the most nished pulp.

So far as relates to the subject-matter of the five first claims, hereinafter set forth, any other mode of heating thecirculating liquid mightbe adopted, such as an exterior boiler or coil or a coil within the maindigester.

Having thus described our improvement, what we claim as our invention,and desire to secure by Letters Patent, isi 1. rlhe pulp-digester,incombination with a lower perforated diaphragm having a centralpulp-passage, a circulating tube or tubes connectin g the upperandlowerpart ofthe digester.

2. The pulp-digester, iu combination with a lower perforated diaphragm,a central pulppassage, a circulating tube and pump, to produce acirculation through the mass from bottom to top, or vice versa.

3. The two valves D and F in the pulp-escape tube, for withdrawing aportion of the contents without interfering with the operation withinthe digester.

4. The charging-pipe S, with its double;

valves, for introducing fresh material without disturbing the operation.

5. The combination of pulp-digester, circulating tube, and pump, whenthe fire is applied directly beneath the digester.

6. The continual forcing in of fresh liquid below and upward through themass to be pulped, in combination with the introduction of the freshcharges of the material into the digester above, whereby the cleanerliquid would always be in contact with the pulp most cooked.

JOHN W. DIXON. GEORGE HARDING.

Witnesses:

GEORGE BUGKLEY, BENJN. MOMAKIN, Jr.

